A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of the text, which is the Rockies and their location. It gives a broad overview of the area without going into details. It does not use any pronouns or definite articles that refer to previous information. Why other lines are not chosen? Paragraph 2 starts with "Banff" which is a specific name and does not stand alone. Paragraph 3 starts with "Between" which is a conjunction. Paragraph 4 starts with "If" which is also a conjunction. Paragraph 5 starts with "Accommodation" which is specific and does not stand alone.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the information about the Rockies and where to stay. It gives a conclusion about accommodation costs, which relates to the activities discussed earlier.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues the topic of Banff, which is mentioned in Paragraph 1. This shows a logical order from the general information about the Rockies to the specific information about Banff.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it talks about the area between Banff and Jasper. This shows a logical order from the information about Banff to the details about the Columbia Icefield.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it offers alternatives to ice activities. This shows a logical order from the ice in Paragraph 3 to other activities in Paragraph 4.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects to Paragraph 4 because it talks about accommodation, which is related to the activities mentioned in Paragraph 4. This shows a logical order from activities to where to stay.